ORIGINAL: da Rock
If you choose alcohol, don't use any that has a percentage on it at all. Isopropyl with a percentage on the label has water in it. Any water is too much. Rubbing alcohols are whatever percentage of alcohol that is listed on the bottle. The rest is water. If it's 70% isopropyl, or rubbing alcohol, it's 30% water.
You can buy denatured alcohol at hardwares and home improvements and it's not very expensive. It's 100% alcohol.
Alcohol is hydroscopic and once open 100% soon becomes 95%. It sucks water out of the air. Iso 91% is about the highest stable concentration that is readily available in drugstores. 100% alcohol would have to come from a lab supply store and would cost plenty. Solvent and stove alcohol are about 91% also. Denatured solvent alcohol still has 3% water when sealed at the factory.